Plastic container having a multiple closure

ABSTRACT

An improved closure arrangement for a molded plastic open head container for use in the shipment and/or storage of hot filled items includes an open head cylindrical plastic container body, a first, relatively thin, resilient, plastic diaphragm closure including an inverted channel provided at the periphery thereof, with the inverted channel being adapted for positioning downwardly over the periphery of the open end of the container body, and an outer closure fabricated of a material substantially more rigid than the plastic material of the diaphragm closure and including inverted channel means provided at the periphery thereof and adapted for positioning downwardly over the container body and diaphragm closure means in order to close the open end of the container body. At least one pressure release opening is provided in the outer closure, and the diaphragm inner closure means is susceptible of flexing in response to pressure differentials created within the closed container such that internal pressure changes are normalized by flexure of the diaphragm closure means, with the substantially rigid outer closure member being retained in its normal strength imparting position.

United States Patent [72] Inventor Roy G. Chm-an PrimaryExaminer-Ralphael H. Schwartz Oak Lawn, Ill. Attorneys-Roland L. Engel,Daniel W. Vittum, Jr. and [21] Appl. No. 861,512 Gomer W. Walters [22]Filed Sept. 26, 1969 [45] Patented Mar. 2,1971 [73] Assignee BennettIndustries, Inc. ABSTRACT: An improved closure arrangement for a moldedpeotone,m plastic open head container for use in the shipment and/orContinuation f application s storage of hot filled items includes anopen head cylindrical 742,773, Ju|y 5 1968, now abandoned plasticcontainer body, a first, relatively thin, resilient, plastic diaphragmclosure including an inverted channel provided at the periphery thereof,with the inverted channel being adapted for positioning downwardly overthe periphery of the open end of the container body, and an outerclosure [54] PLASTIC CONTAINER HAVING A MULTIPLE fabricated of amaterial substantially more rigid than the CLOSURE plastic material ofthe diaphragm closure and including in- 2 Claims, 6 Drawing Figs vertedchannel means provided at the periphery thereof and adapted forpositioning downwardly over the container body U.S. and diaphragmclosure means in order to close the open end [51] 365d 41/02 of thecontainer body. At least one pressure release opening is of Search 46,provided in the outer closure and the diaphragm inner closure 63,66 72,83 means is susceptible of flexing in response to pressure dif- [56]References Cited ferentials created within the closed container suchthat internal pressure changes are normalized by flexure of the UNITEDSTATES PATENTS diaphragm closure means, with the substantially rigidouter 3,184,524 5/1965 Whiteford HO/(Plastics Digest) closure memberbeing retained in its normal strength impart- 3,425,4 7l 2/1969 Yates,Jr ..L 220/29-X ing position.

44 3 A 46 2 4 28 2 I I I 60 PLASTIC CONTAINER HAVING A MULTIPLE CLOSUREThis application is a continuation of Us. Ser. No. 742,773, filed Jul.5, 1968, and now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventiongenerally relates to plastic container sealing arrangements, and moreparticularly is concerned with a closure arrangement for plastic drums,pails, and other similar containers that are especially adapted to-befilled with heated materials (such as foodstuffs, chemicals, or thelike) and sealed immediately thereafter.

2. Description of the Prior Art The prior art contains numerous examplesof attempts to design closure arrangements adapted for use with plasticdrums and pails. This proliferation of design in the field of plasticcontainers has, in large measure, resulted from the obvious advantagesof plastic over conventional materials such as steel. A plasticcontainer suitable for shipping and storage would be more economicalthan a similarly sized metal container by reason of the comparativelyhigher cost of conventionally utilized materials in relation to plastics(such as polyethylene). Moreover, problems of corrosion, which oftenarise with metal containers, could be avoided since plastics aregenerally more resistant than metals to corrosion and other similarforms of attack. Additionally, the effective substitution of plastic formetal in a commercial shipping container results in significanteconomies with respect too the weight of the container. However, despitethese advantages, full utilization of plastic for commercial shippingand storage containers has not been realized because of difficultiesinvolved in providing acceptable sealing arrangements for use with aplastic con tainer body.

One problem has been encountered in the case of plastic containersdesigned for use in shipping and/or storing foodstuffs and other similarproducts which are introduced into the container in a heated condition,with the container being immediately closed while the contents are stillhot for reasons of convenience, sanitation, or the like. Where plasticcontainer bodies are utilized for such containers, problems have beenexperienced due to the action of the heated contents increas ing thepressure within the container as cooler air trapped between the contentsof the container and the closure is heated by the contents ofthecontainer. More particularly,

when such heating and pressure increase is experienced, containerarrangements of the prior art have'experienced an outward swelling ofthe plastic container which is relatively weaker than the conventionalmetallic closures used with such containers. Likewise, the normally flatplastic bottoms of such containers have on occasion bowed outwardlythereby diminishing the stability of the container and, as a practicalmatter, preventing the stacking thereof.

Similar problems are encounteredwhen a cold filled plastic container isclosed and then heated so as to warm the contents, an action whichcauses the same increase in temperature and pressure within the closedvolume of the container.

Accordingly, a primary object of the present invention is to provide aclosure arrangement for a plastic container body which can be utilizedwith hot filled contents without the objectionable side effects thathave been experienced with the prior art.

A related object is to provide an arrangement of the character describedwhich utilizes conventional filling and closure machinery for thecontainers of the present invention.

Yet another object is to provide an arrangementof tht. characterdescribed utilizing an inner flexible diaphragm seal to absorb pressureincreases within the closed container.

SUMMARY or THE INVENTION In accordance with the present invention, animproved closure arrangement for a molded plastic open head container intended for use in shipment and/or storage of hot filled contentsincludes, in combination with an open end container body having asidewall structure and a bottom wall structure formed integrallytherewith at one end thereof, with the other end of the container bodybeing open, a relatively thin, flexible, plastic inner diaphragm closurehaving an inverted channel provided at the periphery thereof. Thediaphragm closure, which has a generally disclike center section capableof flexing in response to pressure changes within the sealed container,is adapted for positioning downwardly over the periphery of the open endof the container body with the inverted channel member sealinglyengaging the sidewall structure thereof and .with the disclike centersection extending downwardly into the container body. An outer closure,fabricated of a material substantially more rigid than the plasticmaterial of the container body, includes an inverted channel provided atthe periphery thereof and a generally disclike center section. The outerclosure is adapted for positioning downwardly over the container bodyand diaphragm closure means with the inverted channel fitting downwardlyover the inverted channel on the diaphragm closure and with the disclikecenter section of the outer closure being spaced apart from the disclikecenter section in order to close the open end of the container body.Means are provided for effecting an interlock between the outer closuremeans and the container body, and at least one pressure release openingis provided in the outer closure, whereby changes in pressures withinthe sealed container are normalized by flexure of the diaphragm closure,with the outer closure and the container body retaining their normalconfigurations.

DESCRIPTION OF THE DRAWING The foregoing and other objects, advantages,and features of the subject invention will hereinafter appear, and, forpurposes of illustration, but not of limitation, exemplary embodimentsof the present invention are illustrated in the accompanying drawing, inwhich:

FIG. 1 is a cross-sectional, side-elevational view of a container andclosure arrangement produced in accordance with the present invention;

FIG. 2 is an exploded view thereof;

FIG. 3 is a top plan view of the arrangement shown in FIG. 1; r

FIG. 4 is a plan view of the arrangement thereof with the outer closureremoved;

FIG. 5 is an enlarged cross-sectional view showing the assembledcontainer and closure arrangement and also the manner in which handlemeans are attached to the container; and

FIG. 6 is a fragmentary side-elevational view showing one feature of thecontainer.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to the drawing, acomposite container 10, comprising an open head container body 12, andouter closure 14, and an inner diaphragm closure 16, is illustrated.Container body 12 comprises a generally cylindrical sidewall structure18 and an integrally formed bottom wall structure 20. Sidewall structure18 has a larger diameter upper portion 22 and a somewhat smallerdiameter portion 24 therebelow, with an angular inclined band member 26integrally formed between portions 22 and 24. The presence of band 26enhances the strength of the container body 12. An inverted U-shaped rim28 is provided at the top edge of the container body 12. As shown in thedrawing, the sidewall structure 18, including both upper and lowerportions 22, 24 thereof, may advantageously be tapered inwardly towardthe bottom to facilitate the stacking thereof in a nested fashion.

As shown in FIGS. 1 and 2, bottom wall structure 20 is offset upwardlyslightly, so that an annular rim 30 formed by the lower edge ofgenerally cylindrical sidewall portion 24 provides the surface on whichthe container body rests. A similar annular rim 32 is provided centrallyof the bottom wall structure and likewise provides a bearing surface onwhich the container rests.

A pair of handle-mounting means are provided at diametrically opposedpoints on container body 12. As best shown in FIGS. 5 and 6, handlemounting means 60 comprises an open bottomed enclosure 62 which ispreferably integrally molded with container body 12. Enclosure 62 has ininclined curved upper surface 64, a pair of sidewalls 66, 68, and anouter wall 70, with an opening 72 therethrough. The end of aconventional wire bail 74 (not shown in FIG. 6) is pivotally mountedthrough opening 72. Thus, bail 74 is easily pivotable from a restposition to a raised carrying position.

Diaphragm closure 16 comprises a generally flat center disc 34, anannular outer U-Shaped rim 36, adapted to fit downwardly over rim 28 onthe container body. Rim 28 is connected with center portion 34 by meansof an annular inclined band 38 which'extends downwardly into theinterior of the container body such that a space is provided betweenclosure 14 and the center disc 34 for a purpose that will hereinafterappear. A pair of annular grooves 39 may be advantageously molded indisc section 34 in order to increase the strength of diaphragm closure16. As best shown in FIG. 5, rim 36 and band 38 are so configured as tosealingly fit over the open end of container body 12. Diaphragm closure16 is relatively thin (i.e., of the order of magnitude of about 0.0125inch thick) and is capable of flexing for a purpose that willhereinafter appear.

The container body 12 and diaphragm closure 16 produced in accordancewith the present invention are preferably formed from a suitable,semirigid plastic. An especially preferred plastic is polyethylenehaving a density ranging between 0.941 and 0.965 grams per cubiccentimeter (ASTM test D-l505-63T) and a melt index ranging between 0.1and 25.0 (ASTM test D-1238-62T). Where the latter preferred polyethyleneis employed in producing a blow-molded container or diaphragm closure,the melt index preferably ranges between 0.1 and 0.5, whereas when it isemployed in producing an injection molded container or diaphragmclosure, the melt index preferably lies between 4.0 and .0. Of course,as will be obvious to those skilled in the art, the container body anddiaphragm closure may be constructed or fabricated from various othersuitable materials and by a variety of manufacturing processes such asinjection molding.

Closure 14 comprises a generally flat center disc 40 and an invertedperipheral bead 42 provided at the periphery thereof. A skirt 44 dependsfrom the outer portion of bead 42 and terminates in a plurality ofspaced lugs 46. Each lug 46 is provided with a slot 48 which is adaptedto receive a tool to be utilized in removing the closure from thecontainer in a manner that will hereinafter be described. A pair ofannular grooves 50, 52 are formed in the center disc 40 of the closurein order to impart strength thereto.

A plurality of openings 54 are provided in center portion 40 of closure14 in order to permit air or other gas to pass therethrough as willhereinafter be described in detail. The exact number of openings and theorder of placement thereof is not critical. It is only necessary that asufficient number of openings be provided in order to permit the firstpassage of air or other gas therethrough.

Closure 14 is fabricated of a material substantially more rigid than theplastic from which container body 12 is fabricated. Among such materialsare metals, such as steel and the like, and, in addition, the closuremay be molded, preferably by conventional injection-molding techniques,from fiber impregnated plastic. A suitable fiber impregnatedplastic-supporting collar comprises approximately 70 percent highdensity polyethylene and about percent asbestos fiber. Asbestos fiber ofthe thixotropic flow-type, for example, anthophyllite asbestos, ispreferably employed. Of course, as will be obvious to one skilled in theart, various other plastics and fibers, as well as other percentagecompositions may be employed, so long as the closure is substantiallymore rigid than the plastic material of the container body 12.

The closure arrangement of the present invention is utilized in thefollowing manner. Container body 12 is first filled with the heatedcontents to a level approximately the dotted line level denoted by thereference character B in FIG. 5. Diaphragm closure 16 is next positionedover the open mouth of the container, with the rim 36 and inclined band38 contacting rim 28 and upper sidewall portion 22. Outer closure 14 isthen placed downwardly over the container body and diaphragm closure,and lugs 44 are crimped inwardly to the position shown in FIGS. 1 and 5,thereby locking the closure in position and sealing the contents of thecontainer.

At this point, due to the heated condition of the contents of thecontainer, the temperature of the air in the space between center disc34 of diaphragm closurel6 and level B increases and pressureinstantaneously builds up within the closed container. However, ratherthan the increased pressure being absorbed by an outward bowing of thesidewall or bottom wall structures of the container body, the centerdisc 34 of diaphragm closure 16 flexes upwardly in the direction shownby the arrow A in FIG. 5 so as to equalize pressure within the containerwith the ambient pressure (the position for center disc 34 after suchflexure being shown in broken lines in FIG. 5). However, because of theplurality of openings 54 provided in the center disc of outer closure14, pressure is not built up in the space between diaphragm closure 16and outer closure 14, and hence outer closure 14 and container body 12retain their respective normal configurations.

Thus, in accordance with the present invention a simple, easily usedarrangement has been provided for equalizing the pressure within aclosed container with ambient pressure without structurally modifyingthe container body or the outer closure thereof. Even if the containeris not ordinarily filled with heated material, if after filling andsealing the container is thereafter subjected to heating, any pressurethat builds up within the space between level B and diaphragm closure 16will immediately be equalized with the ambient pressure by flexure ofthe diaphragm closure. Likewise, if the pressure between the diaphragmclosure and level B for any reason diminishes after sealing, thediaphragm closure will flex in the opposite direction to normalize thepressure within the container to ambient conditions. Of course, as willbe obvious to those skilled in the art, pressure release means otherthan openings 54 in closure 14 may, if desired, be employed. In allevents, however, the present invention provides an arrangement in whichthe sidewall structure of container body 12 retains its originalgenerally cylindrical configuration, and the closure 14, formed of amaterial substantially more rigid than the plastic of the containerbody, retains-its configuration and contributes strength to the open endof the molded plastic container body.

Iclaim: 1. A scalable container comprising: an open end plasticcontainer body having an inwardly tapered sidewall structure and abottom wall structure formed integrally therewith at one end thereof,with the other end of the container body being open; a relatively thin,flexible, plastic inner diaphragm closure including a generally disclikecenter section and an inverted channel provided at the peripherythereof, with the inverted channel being separated from the disclikecenter section by an inclined band of substantial width, the said bandbeing tapered to substantially the same degree as the container bodysidewall structure; with the diaphragm closure being adapted forpositioning downwardly over the periphery of the open end of thecontainer body with the disclike center section extending downwardlyinto the container body,

with the inverted channel being adapted for sealing engagement with thesidewall structure of the container body adjacent the open end thereof,

with the inclined band being adapted to tightly contact the sidewallstructure of the container body, and

with the diaphragm closure being susceptible to flexure in response topressure changes within the sealed container,

an outer closure fabricated of a material substantially more rigid thanthe plastic material of the container body and including a generallydisclike center section and an inverted channel provided at theperiphery thereof;

with the said outer closure being adapted for positioning downwardlyover the container body and diaphragm closure in order to'close theopejnend of the container body, and

with the disclike center section of the outer closure being spaced aparta substantial distance from the disclike center section of the diaphragmclosure so as to permit substantial flexure of diaphragm closure in anaxial direction toward the outer closure without coming into contacttherewith, pressure release means for the outer closure, and means foreffecting an interlock between the outer closure and the container body,

whereby changes in pressure within the sealed container are absorbed byflexure of the diaphragm closure, with the outer closure and thecontainer body retaining their respective normal configurations.

2. A sealable container, as claimed in claim 1, wherein the pressurerelease means comprises at least one opening in the disclike centersection of the outer closure.

1. A sealable container comprising: an open end plastic container bodyhaving an inwardly tapered sidewall structure and a bottom wallstructure formed integrally therewith at one end thereof, with the otherend of the container body being open; a relatively thin, flexible,plastic inner diaphragm closure including a generally disclike centersection and an inverted channel provided at the periphery thereof, withthe inverted channel being separated from the disclike center section byan inclined band of substantial width, the said band being tapered tosubstantially the same degree as the container body sidewall structure;with the diaphragm closure being adapted for positioning downwardly overthe periphery of the open end of the container body with the disclikecenter section extending downwardly into the container body, with theinverted channel being adapted for sealing engagement with the sidewallstructure of the container body adjacent the open end thereof, with theinclined band being adapted to tightly contact the sidewall structure ofthe container body, and with the diaphragm closure being susceptible toflexure in response to pressure changes within the sealed container, anouter closure fabricated of a material substantially more rigid than theplastic material of the container body and including a generallydisclike center section and an inverted channel provided at theperiphery thereof; with the said outer closure being adapted forpositioning downwardly over the container body and diaphragm closure inorder to close the open end of the container body, and with the disclikecenter section of the outer closure being spaced apart a substantialdistance from the disclike center section of the diaphragm closure so asto permit substantial flexure of diaphragm closure in an axial directiontoward the outer closure without coming into contact therewith, pressurerelease means for the outer closure, and means for effecting aninterlock between the outer closure and the container body, wherebychanges in pressure within the sealed container are absorbed by flexureof the diaphragm closure, with the outer closure and the container bodyretaining their respective normal configurations.
 2. A sealablecontainer, as claimed in claim 1, wherein the pressure release meanscomprises at least one opening in the disclike center section of theouter closure.